html,body,.main{
    height: 100%;
}

.main{
    display: flex;
    flex-direction: column;
    .topbar{
        height: 50px;
        // background-color: rgba(161, 161, 161, 0.112);
        background-color: white;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        z-index: 100;
    }
    .box{
        flex: 1;
        // background-color: skyblue;
        padding-top: 50px;
    }
}